Access Point with XB6 Gateway

I have an XFI ADVANCED GATEWAY (XB6). I understand that Xfinity gateways don't have a guest network, aside from the Xfinity hot spots. Is that correct? If so, can I simply connect an access point with a guest network to the gateway? We have occasional guests stay in an extra bedroom in our home and I would like to provide those guests with a different WiFi password. I do realize that there's a risk with security between our home devices and guest devices without a true guest network, but I'm looking for a simple, temporary, straightforward fix to test. I'm trying to avoid dealing with putting the gateway in bridge mode. Is there a certain way I'd have to connect the access point? I have limited knowledge here and am looking for something simple and straightforward. Any access point recommendations and how to properly set up would be appreciated!